CSE 2431 Operating Systems Midterm (Champion)

I have a midterm coming up on Thursday and am feeling kind of nervous for it. Not sure how to study for it exactly, Champion kind of goes on useless tangents so it's kind of hard to pay attention or gauge what is important. Is there anything I should focus on more specifically? how is the exam structured? are there any study guides/sample exams out there? Any advice would be appreciated.